FERNANDES, M. S. M.; http://lattes.cnpq.br/0782679173169516; FERNANDES, Maniza Sofia Monteiro.
Abstract:
In last recent years , a high interest in the biotechnological potential of microalgae was noted,
mainly due to identifying several substances synthesized by these organisms . Their huge
biodiversity allied to genetic improvement and establishing cultivation technology on a large
scale used to allow microalgae to be used in various applications , specially in treatment of
wastewater from industrial processes , mitigating the greenhouse effect by assimilating carbon
dioxide (C02 ) and the biofuels production, such as biodiesel and ethanol. Moreover, in
microalgae production, we noted some problems during separation with a view to the need to
preserve biomass, particularly as regards to the characteristics phones. Among the various
microalgae separation methods, in which are the most commonly centrifugation used, such as
filtration and flocculation and in certain cases where the dimensions are very small, the
separation through rennet addition is used, which are constituted by metal salts which can
damage the chemical composition of the cell and prevent the use of medium after separation.
So it's necessary to seek new techniques for microalgae separation that do not modify its
characteristics, such as the case of separation processes that has the advantage not to break
the cell structure and to allow greater separation depending on the microalgae's porosity, and
beyond, the permeate from separation can be reused as a mean of cultivation of microalgae. In
this context, this study aims to evaluate the potentiality of using reverse osmosis membranes
(RO ) and Ceramic membranes for separing microalgae Chlorella sp reusing the culture
medium derived from the separation in order to reduce operating costs and impacts by
inappropriate release of waste liquid into the soil . Daily monitoring of algal growth was
performed after inoculation through cell density elaborating growth curves from aliquots drawn
in triplicate of photobioreactors and erlemeyeres daily, we also made the chlorophyll and
productivity for each sample studied . We obtained good results on both separation types,
comparing the reuse of the addition of 250mL and 500mL of the RO permeate into the inoculum
volume, we reached a population of 3,3x107 cel.mL"1 and 2,86x107 cel.mL"1, respectively ,
whereas for separatin by Ceramic membrane using the same RO conditions, we obtained
growth of 4,1x107 cel.mL"1 for 250mL permeate and 3,40x107 cel.mL"1 for the 500 mL
permeate. Regarding production versus energy consumption, the membrane separation by RO
presented an energy absorption of 3,96Kw.h/m3 while we obtained 0,510Kw.h/m3 for the
Ceramic membrane process, showing therefore a very promising alternative , since there was a
greater energy costs reduction and a higher cell productivity, thus making it a technology
economically and environmentally correct in microalgae Chlorellas sp cultivation and
separation.